Exercise :: Probability  General Questions
 Probability  Important Formulas
 Probability  General Questions
1.  Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5? 

Answer: Option D Explanation: Here, S = {1, 2, 3, 4, ...., 19, 20}. Let E = event of getting a multiple of 3 or 5 = {3, 6 , 9, 12, 15, 18, 5, 10, 20}.

2.  A bag contains 2 red, 3 green and 2 blue balls. Two balls are drawn at random. What is the probability that none of the balls drawn is blue? 

Answer: Option A Explanation: Total number of balls = (2 + 3 + 2) = 7. Let S be the sample space.
Let E = Event of drawing 2 balls, none of which is blue.

3.  In a box, there are 8 red, 7 blue and 6 green balls. One ball is picked up randomly. What is the probability that it is neither red nor green? 

Answer: Option A Explanation: Total number of balls = (8 + 7 + 6) = 21.
n(E) = 7.

4.  What is the probability of getting a sum 9 from two throws of a dice? 

Answer: Option C Explanation: In two throws of a dice, n(S) = (6 x 6) = 36. Let E = event of getting a sum ={(3, 6), (4, 5), (5, 4), (6, 3)}.

5.  Three unbiased coins are tossed. What is the probability of getting at most two heads? 

Answer: Option D Explanation: Here S = {TTT, TTH, THT, HTT, THH, HTH, HHT, HHH} Let E = event of getting at most two heads. Then E = {TTT, TTH, THT, HTT, THH, HTH, HHT}.
